The field of the invention is tissue repair and volume reduction, for example, lung repair and volume reduction.
End stage emphysema can be treated with lung volume reduction surgery (LVRS) (see, e.g., Cooper et al., J. Thorac. Cardiovasc. Surg. 109:106-116, 1995). While it may seem counter-intuitive that respiratory function would be improved by removing part of the lung, excising over-distended tissue (as seen in patients with heterogeneous emphysema) allows adjacent regions of the lung that are more normal to expand. In turn, this expansion allows for improved recoil and gas exchange. Even patients with homogeneous emphysema benefit from LVRS because resection of abnormal lung results in overall reduction in lung volumes, an increase in elastic recoil pressures, and a shift in the static compliance curve towards normal (Hoppin, Am. J. Resp. Crit. Care Med. 155:520-525, 1997).
While many patients who have undergone LVRS experience significant improvement (Cooper et al., J. Thorac. Cardiovasc. Surg. 112:1319-1329, 1996), they have assumed substantial risk. LVRS is carried out by surgically removing a portion of the diseased lung, which has been accessed either by inserting a thoracoscope through the chest wall or by a more radical incision along the sternum (Katloff et al., Chest 110:1399-1406, 1996). Thus, gaining access to the lung is traumatic. and the subsequent procedures, which can include stapling the fragile lung tissue, can cause serious post-operative complications.